The EPA says half a million of
VW's cars violate the law in the US alone. The company's stock
price is plummeting, and VW has already been hit with a lawsuit
filed on behalf of car owners.

But what does all of this mean
for the environment?

Judging by VW'sown recent
admission, we're
looking at 11 million cars on the road that have the
cheating equipment installed.

In the US, affected VW
vehicles are putting out up to40 timesas muchnitrogen oxide (NOx)as they are supposed to, according to the
EPA. While that is most likely a pretty high estimate, it's still
a very big deal.

For one thing, NOx is a nasty
pollutant that, in addition to occasionally contributing to a
warmer planet, can exacerbate dozens of health conditions,
including asthma, bronchitis, and emphysema.

Beyond pollution

But the actual pollution created as a result of VW's swindle may
be just the tip of the iceberg.

Reuters

The EPA has created rules and regulations
around car emissions designed to reduce the amount of harmful
pollutants our vehicles put out. Unfortunately for carmakers,
these rules often affect a car's gas mileage and how it performs
on the road. In the case of most "clean" diesel engines, you're
essentially trading a more thrilling ride for environmental
friendliness.

And as Travis Bradford, the
director of the energy and environment concentration at
Columbia University's School of International and Public Affairs,
told Business Insider, the EPA has decided this trade-off is
critical, not just for our health and safety, but for the health
of the planet.

Oftentimes, however, the controls
come with a catch: They can be turned on and off. In VW's case,
the company fudged the equipment so it would turn on only when it
was being tested — and turn off the rest of the time.

The result? The cars were more
fun to drive but worse for the environment. That is the
exactopposite of the
trade-off the EPA has outlined.

"This is tantamount to theft of
public property," Bradford told Business Insider.
"You've established rules under which you have to operate
and you have willfully circumvented those rules. This is
company-killing kind of stuff."

How diesel went green

People for years stopped buying
diesel-powered cars, which had been all the rage in Europe thanks
to their fuel economy. They weretoo dirty, at least environmentally speaking,

Compared with plain old gas
vehicles, they put out far more gag-inducing pollutants, as
anyone who has ever driven behind a dusty old 18-wheeler should
know.

But the VW cars at the center of
the controversy are equipped with special technology— technology that has since been
implemented indozens of other small diesel
vehicles— that can
supposedly slash how much NOx its diesel-powered vehicles put
out.

In larger vehicles like trucks,
that
technology works by treating the car'sexhaust with a solution of a chemical
calledurea. When the urea reacts with water and the
pollutants in the car's tailpipe, it converts them into two
less-harmful compounds — mainly nitrogen and water.

In smaller vehicles, however, it
has been much tougher to come up with the technology that
accomplishes these goals. So when VW introduced it, it was huge
news for carmakers.

The new technology enabled a bit
of arenaissance for diesel
vehicles: Wealthy but
environmentally conscious drivers started buying Audis, Mercedes,
and VWs with the engines, which promised to provide a fun, more
powerful drive while delivering better mileage and less toxic
emissions.